The BC30 has a dual LED system for both a flood and spot beam. It uses two 18650 batteries inside the main light housing. The batteries are not included, but some merchants sell bundles with various battery options.

Review: Bringing 18650 batteries to bicycling

Review by Nathan Hinkle, Nov. 7, 2015, 4:30 p.m.

Fenix is a popular manufacturer of high-powered and reliable flashlights. The company has recently started producing lights specifically designed for biking, but with designs heavily influenced by the prosumer flashlight market. The BC30 is a single piece light containing two 18650 lithium batteries and two Cree LEDs. These form a "dual distance" optic which combines a flood and throw pattern. The light is advertised as an 1800 lm light, but the maximum sustained output is only 1200 lm. A remote switch is included which boosts the output to 1800 lm when the button is depressed. The BC30 is large and heavy, but offers a level of flexibility not found in many other headlights. Read on for an introduction to modern rechargeable batteries, or if you're already an 18650 fan, skip to the full review of the light.

Why you (should) want 18650 batteries

The 18650 cell (for 18mm diameter, 65mm length) is the most common commercially available lithium rechargeable cell, and is the same type of cell used in Tesla electric cars. Cell capacity is rated in mAh, with common capacities ranging from 2100 to 3400 mAh. How long a battery of a given capacity will last depends on many factors, but the higher the capacity the longer it will last. Higher capacity cells typically weigh a bit more and cost a bit more than their lower capacity counterparts.

Most bike headlights these days use a single 18650 battery internally, which is recharged through a USB port on the light. In most lights the battery is not user accessible. A few lights have a removable battery but contain the 18650 cell in a proprietary casing. For example, the image above shows the proprietary battery packs for the Cateye Volt 700, Cygolite Expilion, and Serfas TSL, along with a standard 18650 protected cell. If you want extras of these proprietary packaged batteries, you have to pay $30-50 for a single battery pack which can't be charged in a standard charger or used in any other lights. With the BC30 (and a select few other lights like the Lezyne Super Drive XL) the batteries are directly accessible, meaning you can get as many extra batteries as you want, swap them out any time, and charge them with any standard charger. For people doing really long rides, or who just don't want to worry about running out of charge on a ride, this setup is a great choice.

That level of flexibility is awesome, but for the casual rider it may not be worth the hassle. The BC30 does not have a built in charger, and the batteries are not included with the light, meaning you have to buy both of those separately. You also have to be careful with handling 18650 batteries. They have a very high energy density, so if they're overcharged, overdischarged, or shorted they can cause a fire. Some 18650 batteries are "bare cells". In certain lights they can give higher performance (although it shouldn't make a difference for the BC30), but are more likely to become a hazard if not taken care of. Protected cells have a small circuit built into the top of the battery which prevents overdischarge, overcharging, and short circuits. The protection circuit adds a couple millimeters of length, so they won't fit in some lights, but they do fit in the BC30. In general I would recommend protected cells though – they cost a bit more, but it's worth the extra peace of mind in my opinion.

For specific battery recommendations, scroll down to the buying advice at the end of this review.

On to the light itself...

Beam and output

The BC30 has some of the best designed optics and brightest output of any light under $250 – and even with batteries and charger it shouldn't run you more than $150 for the whole package. The dual beam design casts a wide flood of light near the bike, easily illuminating a 2 lane road, and a narrower beam extends far into the distance. At the full 1200 lumens it feels like having car headlights. Fenix tests to the FL1 Standard, and independent lumen measurements by MTBR put the actual output on the highest mode at 1280 lm. The downside to this wide dual beam is that at low outputs it's not very bright in any one spot. A typical light with narrow optics will still cast a reasonably bright beam on its low setting at 200 lumens because that light isn't spread over a wide area. When the BC30 is on its lowest setting of 100 lumens the light is spread over a much larger area, so the amount of light at any given point is less.

Fortunately, with the dual batteries, the BC30 can last for 11 hours on its medium setting at 200 lumens or 5 hours at 500 lumens, which is more than enough light for most types of riding. And, if the lowest setting is enough for your ride, the runtime is estimated to be at least 20 hours. The light has a total of 4 output levels (not including the boost), as well as a flashing mode. The flash mode is not particularly attention grabbing – it's a very slow single flash. The good news is that it's not too distracting, like some fast strobing lights are, but it's also less likely to capture the attention of approaching drivers.

The "boost" mode can be activated by plugging in the included remote switch and holding the button down. The LEDs aren't meant to be driven at this output level for extended periods of time, so the boost can only be activated for 20 seconds at a time. The usefulness of this feature depends heavily on the type of riding you're doing. For mountain biking – which is what the light primarily seems to be marketed for – the boost mode is nearly useless. The times when you would most want to boost the light are when you can least afford to occupy one hand by holding down a button. It would be nice if pushing the button would boost the beam until either pushed again or until 20 seconds passed. For urban and road riding though, where it's easier to control the bike, the feature can be quite handy. Much as you might flash the high beams in a car to signal another driver, the boost mode can be used to quickly grab the attention of other people nearby you – for example, flashing a driver who you think is about to turn across your path. It can also be handy if you see possible debris in your path and want a bit more light for a moment. A more useful design for the remote switch might have been a single press to switch between modes (like the regular button on the light), and a press-and-hold to activate the boost.

Battery life

Battery life will depend on the particular batteries you use. I tested the light with Olight 3400 mAh protected 18650 batteries provided by BestLight.io. With these batteries the light lasted about an hour and a half on high. As the batteries started to lose charge the light automatically switched to a lower output level to keep running. The light finally shut down after a total runtime of 4:30 hours. The output of some lower quality lights will drop as the battery voltage drops, but Fenix uses digital output regulation to ensure the brightness remains constant throughout the runtime.

The two batteries sit in a removable tray which slides into the back of the light. The battery compartment has a very tight seal, which makes it a bit difficult to open and close. To open the battery compartment you twist a metal ring 90° and pull out. The metal ring can pop out if you pull too hard, so I found it best to pinch in on the tabs while pulling out (see the photo below). To close the compartment I typically have to use two fingers to clamp down on the tray while closing the latch with the other hand. The tight battery compartment means it can be a bit of a hassle to change batteries in the middle of a ride, especially if you don't have a secondary light source to see what you're doing.

Mounting

The BC30 is not a good choice for those concerned about every gram. The mount for the BC30 is huge and heavy – it weighs as much as some small lights do alone. It also is not quick releasable. Installing it requires no tools, but does take a few minutes as you must loosen the large fastening screw all the way, then tighten it all the way down. The good thing is the mount is incredibly stable. Riding over various bumps and rough surfaces caused no movement of the light.

The remote switch comes with a small piece of Velcro which is used to mount it anywhere on the handlebars. I found it best to put the switch just to the left of my right shifters/brakes, where I could easily push it with my thumb while riding.

Overall impressions

The Fenix BC30 is definitely unconventional in the field of modern bike headlights, and it has a lot to offer. It features a superb beam pattern, high output, stable mounting, and the best flexibility in battery options you're likely to find. This light is a great choice for people riding long distances or needing a lot of light output. For hardcore mountain biking this may be the ultimate single-piece light. That said, for the casual commuter it's likely overkill – few urban riders need 1200 lumens, the light is large and heavy, and the battery life may not be necessary if you only do short rides.

Purchasing suggestions

Fenix products are harder to find in stores than other bike light brands. Some retailers carry their flashlights, but I've yet to see a Fenix light in a bike shop. There are many different online retailers though, and there are always sales happening. Below are a few particular recommendations which should serve you well, but there may be better deals out there if you hunt for them.

The all in one package, via BestLight.io:

BestLight.io is an authorized Fenix online seller, and generously provided the light for this review. You can get 10% off any product on their store (not just bike lights) using the coupon code "BLDBFAN". They sell the BC30 for $100, which comes out to $90 with the coupon. They also offer a bundle with the BC30, two 3400 mAh OLight batteries, and a Nitecore MH20 charger for $140, or $125 with the coupon code. This is the best price I've seen for getting the light, batteries, and charger together if you're new to 18650 batteries.

Best high-quality 18650 batteries, KeepPower via Illumn:

The cheapest high-quality and high-capacity protected 18650 batteries available are the KeepPower 3400 mAh, sold by Illumn.com. At $11 each, they're about half the price of most other 3400 mAh protected cells, and use the same Panasonic NCR18650B cell inside as name brands like Nitecore and Olight. These are the top choice of many flashlight addicts, and it's hard to find a better bargain.

Charger options:

There are many 18650 chargers to choose from. My personal favorite is the simple but effective Nitecore i2. It can charge 2 batteries at once, and digitally measures the battery voltage and optimizes charging to maximize the lifetime of the battery. It plugs into a standard wall outlet, and is available on Amazon and from BestLight (remember, 10% off with coupon code).

BestLight recommended the NiteCore UM20, which I tested with this review. It is nearly identical to the i2 charger, but uses a USB cable as the power source instead of a wall outlet. It can also be used in reverse as a USB battery pack to charge other devices. It's the same price as the i2, so if you're into USB charging it's a good deal. However, I encountered numerous frustrations with it – the charger seems to be very picky about the quality of the USB power source, and refuses to charge batteries at all if it doesn't get a steady voltage. It worked great with one of my computers, and poorly with a different computer and several wall plugs. If you do want it, you can get it on Amazon or from BestLight.

Buying from Fenix:

The official Fenix website, fenixlighting.com, has the BC30 for $100 without batteries. Fenix offers various compatible batteries, but the batteries are quite pricey.

Buying from Amazon:

The BC30 is sold by a number of third party Amazon sellers. Most of them bundle batteries and some include a charger. Some listings only include non-rechargeable CR123 batteries. While some of the battery options may be OK, many of these packages include cheap batteries of dubious quality. It's probably best to buy your batteries and charger separately if you're buying on Amazon. I was unable to find any Amazon listings offering just the light for cheaper than the other sources mentioned above.